Anadarko Petroleum Corp. has 100 wells, “maybe a few more,” in the Marcellus Shale alone that are not completed or tied in as they await infrastructure, a company executive said Tuesday.

In Texas another 50 wells in the Maverick Basin are in the process of being completed, and in the Bone Spring play, 20 wells are in “some state” of being drilled, completed or tied in, Senior Vice President Chuck Meloy told energy analysts during a conference call.

Meloy, who heads Worldwide Operations for The Woodlands, TX-based independent, said delays in the Marcellus Shale were not price-related, but “essentially most of that is getting infrastructure built to the wells and tying in. We’re not holding back for price or anything like that.” The Marcellus play, like the Maverick and Bone Spring plays, “are in start-up mode,” he explained.

When asked where Anadarko’s inventory of uncompleted wells may be 12 months from now, Meloy said he had a “sense” that in the Maverick and Bone Spring plays the backlog would be similar to today because the company is planning to increase the number of rigs in the plays, “which will keep the inventory on those along those lines.”

In the Marcellus Shale, however, Anadarko’s backlogged inventory is expected to “come down sharply over the course of the next few months, as we commission and put on line a number of systems for gas gathering, pipelines” and overall midstream infrastructure.

Anadarko, at one time a gas-heavy U.S. producer, has reversed the mix to liquids-rich, CEO Jim Hackett said. U.S. onshore production now is about 70% weighted to oil and natural gas liquids, compared with less than 50% a year ago, he noted. With prices more attractive for liquids, domestic natural gas output isn’t expected to be much higher than today over the next two years.

The independent’s shale plays, however, continue to hold a lot of gas potential, Hackett told analysts. In the Marcellus Shale Anadarko now has about 750,000 gross acres, which have a net risked captured resource potential of “more than 6 Tcf,” he said.

“We are realizing consistent IPs [initial production rates] of more than 7 MMcf/d across our core position in north and central Pennsylvania,” Hackett said. As more infrastructure comes online, “we’re expecting to nearly double our takeaway capacity by the end of the year.”

Another 400,000 gross acres are held by Anadarko in the Eagle Ford Shale, which has an estimated net risked potential of “more than 450 million boe,” said the CEO. The South Texas play already has “gathering, takeaway, processing and water-handling capacity in place…We’re running seven rigs and have plans to ramp up to nine in the first quarter [of 2011].”

In Texas’ Avalon Shale, which includes Bone Spring, Anadarko has 550,000 gross acres. Seven rigs now are running in the leasehold, both operated and nonoperated, and “we’re achieving strong IPs in both plays,” said Hackett. “At least” eight Avalon wells are expected to be completed by year’s end.

Anadarko continues to look for a joint venture (JV) partner for its Eagle Ford leasehold, and it’s also in early days to find a partner to help develop the Niobrara Shale, said COO Al Walker.

Asked why Anadarko would want a partner in the Eagle Ford Shale if it’s “as good as you think,” Walker said the play gives the company “exceptional rates of return,” but if it is able to “get terms acceptable to us, and we continue to get a good rate of return, that’s the motivator. It’s as singular as that.”

Anadarko is using its Marcellus JV “as a footprint” for future partnerships in the Eagle Ford and Niobrara plays, said the COO. Earlier this year an affiliate of Japanese trading giant Mitsui & Co. Ltd. agreed to pay $1.4 billion to acquire a nearly one-third stake (32.5%) in the Marcellus leasehold (see Daily GPI, Feb. 17).

Securing a JV partner for other shale plays is “not to take capital off the table,” said Walker. “We’re not talking about balance sheet improvement but improving our rate of return.”

As to when a partnership may be announced, Walker said it could be any day. “I would tell you that today if someone meets our terms, we have enough data to support that. We’re not looking for critical mass to promote it…and we’re not looking to give it away…Terms are more important than timing.”

With uncertainty about when the Gulf of Mexico may return to pre-moratorium levels, Anadarko, which had planned to spend $1 billion in 2010 in the offshore, reversed some of its “longer cycle” plans to reinvest in “mostly liquids” onshore plays, said Walker.

“We’re mindful how longer-cycle stuff can be brought forward,” he said. “As we move onshore from offshore, we’re both enhancing the short-term cycle of investment and moving things with extremely good rates of return.”